NGC 4631 Group

NGC 4631 Group
Observation data (Epoch J2000)
Constellation(s)	Canes Venatici & Coma Berenices
Right ascension	12h 09m[1][2]
Declination	+30° 02′[1][2]
Number of galaxies	5-27[3][4][1][2]
Brightest member	NGC 4631[4][2]
Other designations
LGG 291[1], NOGG H611[2], NOGG P1 631[2], NOGG P2 642[2]
See also: Galaxy groups and clusters, List of galaxy clusters
v · d · e

The NGC 4631 Group is a poorly-defined group of galaxies, about 25 million light years from Earth in the Coma Berenices and Canes Venatici constellations.

Members

• spiral galaxy NGC 4631 (Whale Galaxy), brightest galaxy in the group ^[4]
• interacting galaxies NGC 4656 and NGC 4657 (Hockey Stick Galaxies)
• dwarf elliptical galaxy NGC 4627, which is a companion of NGC 4631^[5], is also by default a member of the group, although it is not listed in most catalogs

Aside from these four galaxies, however, the determination of group membership is quite variable. The group lies in a relatively crowded part of the sky near the Virgo Cluster, so exact determination of the group membership is extremely difficult. Some studies have estimated that the NGC 4631 Group contains as few as 5 galaxies^[3], while others place the estimate as high as 27^[2]. Additionally, it is unclear as to whether the galaxies near NGC 4631 and NGC 4656/NGC4657 form one large group or two smaller groups^[1].

See also

Virgo Cluster - a large cluster of galaxies that is near the NGC 4631 group

References

1. ^ ^{a b c d e} A. M. Garcia (1993). "General study of group membership. II - Determination of nearby groups". Astronomy and Astrophysics Supplement 100: 47–90. Bibcode 1993A&AS..100...47G. 
2. ^ ^{a b c d e f g h} G. Giuricin, C. Marinoni, L. Ceriani, A. Pisani (2000). "Nearby Optical Galaxies: Selection of the Sample and Identification of Groups". Astrophysical Journal 543 (1): 178–194. Bibcode 2000ApJ...543..178G. doi:10.1086/317070. 
3. ^ ^{a b} R. B. Tully (1988). Nearby Galaxies Catalog. Cambridge: Cambridge University Press. ISBN 0-521-35299-1. 
4. ^ ^{a b c} P. Fouque, E. Gourgoulhon, P. Chamaraux, G. Paturel (1992). "Groups of galaxies within 80 Mpc. II - The catalogue of groups and group members". Astronomy and Astrophysics Supplement 93: 211–233. Bibcode 1992A&AS...93..211F. 
5. ^ H. Arp (1966). "Atlas of Peculiar Galaxies". Astrophysical Journal Supplement 14: 1–20. Bibcode 1966ApJS...14....1A. doi:10.1086/190147. 

External links

• The Whale and the Hockey Stick Astronomy Picture of the Day of 2009 August 21